Modular belts may be furnished with accessories such as flights that may be produced integrally on special flight modules that are connected to standard modules. The flight modules may be connected in rows of single modules as part of a chain or the flight modules may be connected to adjacent rows of modules in a bricklayed fashion. In order to provide greater flexibility for using various types of attachments on the same belt type or for easier repair, it is known to provide specially designed modules with removable accessories. An example of this type of module is shown in U.S. Pat. No. 4,832,183. This design includes a recess within the intermediate section between the links of the belt module such that an accessory (i.e., flight) can be shifted into locking position from the side of the module. Installation or removal of the attachments disclosed in the '183 patent requires space on the side of the belt. This space has to be as wide as the flight itself. If the free side movement is obstructed or belts are running side-by-side, the space for side clearance is not available and installation or removal of the accessory is only possible after the belt has been uninstalled. Such typical applications include vertical pan conveyors in bakeries as schematically shown in FIGS. 1A and 1B. Special belts 10 having a plurality of flights 12 are running side-by-side to carry pans 13 and to move them vertically in the direction of arrow 16. The pans 13 are used to convey baked goods 14. FIGS. 1A and 1B show one pair of belts 10 only. The belts 10 articulate about sprockets 17 in the direction of arrows 18, 19. In the actual application a series of belts are running side-by-side in such a way that a series of pans, which move with the belts from bottom to top, are carried in a large enclosure.
U.S. Pat. No. 6,554,129 discloses snapped on flights, but the system is not safe enough in all applications because it may disengage at high load. For vertical pan conveyors in bakeries as discussed previously, special requirements have to be fulfilled. The loads are usually quite high and the attachments need to be well secured to the belt. In this application, the pans may become jammed and the attachments may be damaged and need to be replaced. Also, the accessory or belt may break completely. In such a case it is desirable to assure that only the removable attachment is damaged and not the belt.
Accordingly, there is a need for removable attachments that allow for secure attachment in a flexible manner. The system should provide for positive fixation of the attachment allowing high loads without risk of disengagement. The system should not require significant side clearance. Also, the system should provide optional disengagement on breakage of the attachment at a calculated limit to protect the belt from damage due to overload.